For postlingually deafened adults to receive maximum benefit from a cochlear implant, they must adapt to a stimulus that is vastly different from the representations of speech stored in their long-term memory. This issue may be particularly relevant for bilateral cochlear implant users, as they must not only adapt to electrical stimulation of one ear, but also to possible asymmetries between ears. Such asymmetries may be exacerbated by the lack of fitting procedures for bilateral implants, as current clinical care recommends fitting each ear separately with no specific procedure to coordinate the implants so that they work best together. The current proposal focuses on this issue, and describes four experiments to investigate the optimization of bilateral cochlear implant fittings. Experiment 1 will test the hypothesis that different procedures for pitch-matching across the two electrodes will result in similar adjustment to the frequency map. Experiments 2 and 3 will test the hypotheses that pitch- and loudness-matching procedures will enhance speech perception and localization abilities in both naive (Experiment 2) and experienced (Experiment 3) bilateral cochlear implant users. Experiment 4 will test the hypotheses that sequentially implanted bilateral cochlear implant users prefer a frequency map that matches that of the longer-implanted ear, while simultaneously implanted bilateral cochlear implant users prefer a map that matches the side with the deeper insertion depth, as that ear should require less adaptation to the frequency shift proposed to exist in cochlear implant users. These experiments will provide valuable public health information with regard to patient outcomes with bilateral cochlear implants, particularly with regard to optimizing their fitting procedures. Furthermore, they will employ innovative techniques, such as a tool that allows the listener to adjust implant parameters in real time. Such techniques are applicable not only to the current proposal, but will likely have widespread application for optimizing of cochlear implant fitting, and reducing the time that patients require to fully adapt to their cochlear implant(s). [unreadable] [unreadable] [unreadable] [unreadable] [unreadable] [unreadable]